KARZ, Afghanistan
— President Hamid Karzai’s helicopter touched down at the family cemetery in a plume of dust Wednesday morning after the rest of the mourners had assembled, arriving by foot and in fleets of armored cars.

Under the white dome of the open-air mausoleum, the president stood for a moment and looked into the open grave that had been cut from a marble floor. The body of Ahmed Wali Karzai — his slain half-brother, the most influential power broker in southern Afghanistan — lay beneath a white sheet.

Black smoke rose from a towering kiln nearby, where the poor residents of this village on the outskirts of Kandahar fire their bricks. U.S. military helicopters circled above. Afghan and American soldiers manned checkpoints for miles around to prevent the Taliban — which claimed responsibility for killing Karzai — from taking aim at the ceremony.

Karzai was shot to death Tuesday in his home by Sardar Mohammad, who had worked alongside him for seven years and who commanded police officers in the villages around Karz, the ancestral home of the Karzai family.

Mohammad, who was fatally shot by Karzai’s guards after the killing, lived in Zakir, a village just down the road from the small tree-shaded family plot where Karzai’s funeral took place.

U.S. and Afghan officials say it is possible that the Taliban may have influenced Mohammad’s decision to kill Karzai. But they also note that Karzai, who wielded enormous power in southern Afghanistan, had many political enemies.

Elsewhere in Kandahar province, officials said, the governor of Helmand province and his intelligence chief were the targets of a remote-controlled bomb attack as they traveled to the funeral Wednesday morning. Both men escaped without injury, but two soldiers were hurt by the blast.

In Kapisa province, northeast of Kabul, five French soldiers were killed in a suicide bombing for which the Taliban claimed credit, officials said. That attack was not linked to Karzai’s funeral, but it underscored the continued volatility in Afghanistan as the United States and other alliance members are trying to transfer security responsibility to Afghan forces.

At the cemetery in Karz, the president bowed his head and appeared to be crying. The crowd surged in all around. Frantic bodyguards shouted and pushed against the mourners in vain.

“Go away, go away — you’ll bring him more sin,” one person shouted. Men in turbans wailed their misery. Cabinet ministers and army generals craned their necks for a view.

The president did not make a sound. Carefully, he stepped down into the grave and knelt over his brother’s body; it is customary here to see the faces of close relatives before they are buried. A web of men closed over the president, interlocking limbs in a hot press of bodies sweating through their clothes.

After a few seconds, Hamid Karzai climbed out of the grave, walking past the burial site of his father, Abdul Ahad Karzai, whose murder in 1999 galvanized his own political ambitions. The president slipped into a waiting car and departed. The gravediggers went back to work.

“It’s tough on us,” said Mahmood Karzai, another of the president’s brothers, who lingered by the grave. “We’re not doing too well. It’s a big loss. It’s a big loss for us.”

“I don’t know why we’re losing these kinds of people one by one,” said Anwar Hamidi, the brother of Kandahar’s mayor and an official in Karzai’s palace. “We are worried.”

Gen. Abdul Raziq, Kandahar’s young police chief and a rising power in southern Afghanistan, was among the last to leave the cemetery. He said associates of Mohammad’s had been arrested and were being interrogated but offered only vague speculation as to the motive behind the killing.

“I hope his brothers will fill the gap and follow his footsteps and keep the tribes together,” Raziq added.

The gravediggers laid shrouds over the body and, on top of that, four concrete slabs. They piled dirt high above the grave and pushed in two saplings when they were done.

“Just leave, just leave this place,” an old man said to those who remained. “This is our way.”

Special correspondents Javed Hamdard in Karz and Sayed Salahuddin in Kabul contributed to this report.